chore(sync-service): Refactor ShapeStatus initialize (#3296)

Based on @alco 's feedback on #3293

Author: robacourt

packages/sync-service/lib/electric/shape_cache/shape_status.ex

@@ -20,7 +20,7 @@ defmodule Electric.ShapeCache.ShapeStatusBehaviour do
     @type stack_ref() :: atom() | stack_id() | [stack_id: stack_id()]
   end
 
-  @callback initialise(stack_ref(), Storage.t()) :: :ok | {:error, term()}
+  @callback initialize_from_storage(stack_ref(), Storage.t()) :: :ok | {:error, term()}
   @callback terminate(stack_ref(), String.t()) :: :ok | {:error, term()}
   @callback list_shapes(stack_ref()) :: [{shape_handle(), Shape.t()}]
   @callback count_shapes(stack_ref()) :: non_neg_integer()
@@ -84,20 +84,27 @@ defmodule Electric.ShapeCache.ShapeStatus do
   @snapshot_started :snapshot_started
 
   @impl true
-  def initialise(stack_ref, storage \\ nil) do
-    last_used_table = shape_last_used_table(stack_ref)
-    :ets.new(last_used_table, [:named_table, :public, :ordered_set])
-
+  def initialize_from_storage(stack_ref, storage) do
+    last_used_table = create_last_used_table(stack_ref)
     meta_table = shape_meta_table(stack_ref)
 
-    if storage do
-      load_from_storage(stack_ref, storage)
-    else
-      :ets.new(meta_table, [:named_table, :public, :ordered_set])
-      :ok
+    case load_table_backup(meta_table, storage) do
+      {:ok, ^meta_table, path} ->
+        Logger.info("Loaded shape status from backup at #{path}")
+        :ok
+
+      _ ->
+        Logger.debug("No shape status backup loaded, creating new table #{meta_table}")
+        create_meta_table(stack_ref)
+        load(meta_table, last_used_table, storage)
     end
   end
 
+  def initialize_empty(stack_ref) do
+    create_last_used_table(stack_ref)
+    create_meta_table(stack_ref)
+  end
+
   @impl true
   def terminate(stack_ref, backup_dir) do
     meta_table = shape_meta_table(stack_ref)
@@ -366,6 +373,20 @@ defmodule Electric.ShapeCache.ShapeStatus do
     def shape_last_used_table(state) when is_map(state), do: state.shape_last_used_table
   end
 
+  defp create_last_used_table(stack_ref) do
+    last_used_table = shape_last_used_table(stack_ref)
+
+    :ets.new(last_used_table, [:named_table, :public, :ordered_set])
+    last_used_table
+  end
+
+  defp create_meta_table(stack_ref) do
+    meta_table = shape_meta_table(stack_ref)
+
+    :ets.new(meta_table, [:named_table, :public, :ordered_set])
+    meta_table
+  end
+
   defp load(meta_table, last_used_table, storage) do
     with {:ok, shapes} <- Storage.get_all_stored_shapes(storage) do
       now = System.monotonic_time()
@@ -412,22 +433,6 @@ defmodule Electric.ShapeCache.ShapeStatus do
     end
   end
 
-  defp load_from_storage(stack_ref, storage) do
-    last_used_table = shape_last_used_table(stack_ref)
-    meta_table = shape_meta_table(stack_ref)
-
-    case load_table_backup(meta_table, storage) do
-      {:ok, ^meta_table, path} ->
-        Logger.info("Loaded shape status from backup at #{path}")
-        :ok
-
-      _ ->
-        Logger.debug("No shape status backup loaded, creating new table #{meta_table}")
-        :ets.new(meta_table, [:named_table, :public, :ordered_set])
-        load(meta_table, last_used_table, storage)
-    end
-  end
-
   defp load_table_backup(meta_table, storage) do
     case backup_dir(storage) do
       nil ->

packages/sync-service/lib/electric/shape_cache/shape_status_owner.ex

@@ -40,7 +40,7 @@ defmodule Electric.ShapeCache.ShapeStatusOwner do
     Logger.metadata(stack_id: stack_id)
     Electric.Telemetry.Sentry.set_tags_context(stack_id: stack_id)
 
-    :ok = ShapeStatus.initialise(stack_id, config.storage)
+    :ok = ShapeStatus.initialize_from_storage(stack_id, config.storage)
 
     Electric.LsnTracker.create_table(stack_id)
 

packages/sync-service/test/electric/shape_cache/expiry_manager_test.exs

@@ -19,7 +19,7 @@ defmodule Electric.ExpiryManagerTest do
   @max_shapes 10
 
   setup %{stack_id: stack_id} do
-    ShapeStatus.initialise(stack_id)
+    ShapeStatus.initialize_empty(stack_id)
 
     expiry_manager =
       start_supervised!(

packages/sync-service/test/electric/shape_cache/shape_status_test.exs

@@ -56,7 +56,7 @@ defmodule Electric.ShapeCache.ShapeStatusTest do
 
     state = shape_status_opts(opts)
 
-    :ok = ShapeStatus.initialise(state, state.storage)
+    :ok = ShapeStatus.initialize_from_storage(state, state.storage)
 
     shapes = Keyword.get(opts, :shapes, [])
 
@@ -357,7 +357,7 @@ defmodule Electric.ShapeCache.ShapeStatusTest do
 
       state = shape_status_opts(table: table)
 
-      assert :ok = ShapeStatus.initialise(state, state.storage)
+      assert :ok = ShapeStatus.initialize_from_storage(state, state.storage)
       shape = shape!()
       assert {:ok, shape_handle} = ShapeStatus.add_shape(state, shape)
       assert [{^shape_handle, ^shape}] = ShapeStatus.list_shapes(state)
@@ -383,7 +383,7 @@ defmodule Electric.ShapeCache.ShapeStatusTest do
 
       state2 = shape_status_opts(table: table)
 
-      assert :ok = ShapeStatus.initialise(state2, state2.storage)
+      assert :ok = ShapeStatus.initialize_from_storage(state2, state2.storage)
       assert [{^shape_handle, ^shape}] = ShapeStatus.list_shapes(state2)
       # consuming backup directory should have removed it after load
       refute File.exists?(backup_file)
@@ -403,7 +403,7 @@ defmodule Electric.ShapeCache.ShapeStatusTest do
 
       state = shape_status_opts(table: table)
 
-      assert :ok = ShapeStatus.initialise(state, state.storage)
+      assert :ok = ShapeStatus.initialize_from_storage(state, state.storage)
       shape = shape!()
       assert {:ok, shape_handle} = ShapeStatus.add_shape(state, shape)
       assert [{^shape_handle, ^shape}] = ShapeStatus.list_shapes(state)
@@ -425,7 +425,7 @@ defmodule Electric.ShapeCache.ShapeStatusTest do
 
       state2 = shape_status_opts(table: table)
 
-      assert :ok = ShapeStatus.initialise(state2, state2.storage)
+      assert :ok = ShapeStatus.initialize_from_storage(state2, state2.storage)
       # Shape from backup should NOT be present after failed integrity
       assert [] == ShapeStatus.list_shapes(state2)
       refute File.exists?(backup_file)

packages/sync-service/test/electric/shapes/monitor_test.exs

@@ -24,7 +24,7 @@ defmodule Electric.Shapes.MonitorTest do
   defp start_stack_status(ctx) do
     Repatch.patch(Electric.Shapes.Shape, :generate_id, fn _shape -> {"hash", @shape_handle} end)
 
-    :ok = Electric.ShapeCache.ShapeStatus.initialise(ctx.stack_id, ctx.storage)
+    :ok = Electric.ShapeCache.ShapeStatus.initialize_from_storage(ctx.stack_id, ctx.storage)
 
     parent = self()